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  <title>Checks if entry exists</title>
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  <div id="layout-content"><div id="function.apcu-exists" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">apcu_exists</h1>
  <p class="verinfo">(PECL apcu &gt;= 4.0.0)</p><p class="refpurpose"><span class="refname">apcu_exists</span> &mdash; <span class="dc-title">Checks if entry exists</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.apcu-exists-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>apcu_exists</strong></span>
    ( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$keys</code></span>
   ) : <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span></div>

  <p class="para rdfs-comment">
   Checks if one or more APCu entries exist.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.apcu-exists-parameters">
  <h3 class="title">参数</h3>
  <dl>

   
    <dt>
<code class="parameter">keys</code></dt>

    <dd>

     <p class="para">
      A <span class="type"><a href="language.types.string.html" class="type string">string</a></span>, or an <span class="type"><a href="language.types.array.html" class="type array">array</a></span> of strings, that
      contain keys.
     </p>
    </dd>

   
  </dl>

 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.apcu-exists-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns <strong><code>TRUE</code></strong> if the key exists, otherwise <strong><code>FALSE</code></strong> Or if an
   <span class="type"><a href="language.types.array.html" class="type array">array</a></span> was passed to <code class="parameter">keys</code>, then
   an array is returned that contains all existing keys, or an empty
   array if none exist.
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.apcu-exists-examples">
  <h3 class="title">范例</h3>
  <div class="example" id="example-420">
   <p><strong>Example #1 <span class="function"><strong>apcu_exists()</strong></span> example</strong></p>
   <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$fruit&nbsp;&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'apple'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$veggie&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'carrot'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">apcu_store</span><span style="color: #007700">(</span><span style="color: #DD0000">'foo'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$fruit</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">apcu_store</span><span style="color: #007700">(</span><span style="color: #DD0000">'bar'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$veggie</span><span style="color: #007700">);<br /><br />if&nbsp;(</span><span style="color: #0000BB">apcu_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">'foo'</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Foo&nbsp;exists:&nbsp;"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #0000BB">apcu_fetch</span><span style="color: #007700">(</span><span style="color: #DD0000">'foo'</span><span style="color: #007700">);<br />}&nbsp;else&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Foo&nbsp;does&nbsp;not&nbsp;exist"</span><span style="color: #007700">;<br />}<br /><br />echo&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />if&nbsp;(</span><span style="color: #0000BB">apcu_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">'baz'</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Baz&nbsp;exists."</span><span style="color: #007700">;<br />}&nbsp;else&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Baz&nbsp;does&nbsp;not&nbsp;exist"</span><span style="color: #007700">;<br />}<br /><br />echo&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$ret&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">apcu_exists</span><span style="color: #007700">(array(</span><span style="color: #DD0000">'foo'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'donotexist'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'bar'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$ret</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
   </div>

   <div class="example-contents"><p>以上例程的输出类似于：</p></div>
   <div class="example-contents screen">
<div class="cdata"><pre>
Foo exists: apple
Baz does not exist
array(2) {
  [&quot;foo&quot;]=&gt;
  bool(true)
  [&quot;bar&quot;]=&gt;
  bool(true)
}
</pre></div>
   </div>
  </div>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.apcu-exists-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li class="member"><span class="function"><a href="apcu_cache_info.html" class="function" rel="rdfs-seeAlso">apcu_cache_info()</a> - Retrieves cached information from APCu's data store</span></li>
   <li class="member"><span class="function"><a href="apcu_fetch.html" class="function" rel="rdfs-seeAlso">apcu_fetch()</a> - Fetch a stored variable from the cache</span></li>
  </ul>
 </div>

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